shared/extra-utils/ffprobe.ts

   1 import { ffprobe, FfprobeData } from 'fluent-ffmpeg'
   2 import { VideoFileMetadata } from '@shared/models/videos'
   3
   4 /**
   5  *
   6  * Helpers to run ffprobe and extract data from the JSON output
   7  *
   8  */
   9
  10 function ffprobePromise (path: string) {
  11   return new Promise<FfprobeData>((res, rej) => {
  12     ffprobe(path, (err, data) => {
  13       if (err) return rej(err)
  14
  15       return res(data)
  16     })
  17   })
  18 }
  19
  20 // ---------------------------------------------------------------------------
  21 // Audio
  22 // ---------------------------------------------------------------------------
  23
  24 const imageCodecs = new Set([
  25   'ansi', 'apng', 'bintext', 'bmp', 'brender_pix', 'dpx', 'exr', 'fits', 'gem', 'gif', 'jpeg2000', 'jpgls', 'mjpeg', 'mjpegb', 'msp2',
  26   'pam', 'pbm', 'pcx', 'pfm', 'pgm', 'pgmyuv', 'pgx', 'photocd', 'pictor', 'png', 'ppm', 'psd', 'sgi', 'sunrast', 'svg', 'targa', 'tiff',
  27   'txd', 'webp', 'xbin', 'xbm', 'xface', 'xpm', 'xwd'
  28 ])
  29
  30 async function isAudioFile (path: string, existingProbe?: FfprobeData) {
  31   const videoStream = await getVideoStream(path, existingProbe)
  32   if (!videoStream) return true
  33
  34   if (imageCodecs.has(videoStream.codec_name)) return true
  35
  36   return false
  37 }
  38
  39 async function hasAudioStream (path: string, existingProbe?: FfprobeData) {
  40   const { audioStream } = await getAudioStream(path, existingProbe)
  41
  42   return !!audioStream
  43 }
  44
  45 async function getAudioStream (videoPath: string, existingProbe?: FfprobeData) {
  46   // without position, ffprobe considers the last input only
  47   // we make it consider the first input only
  48   // if you pass a file path to pos, then ffprobe acts on that file directly
  49   const data = existingProbe || await ffprobePromise(videoPath)
  50
  51   if (Array.isArray(data.streams)) {
  52     const audioStream = data.streams.find(stream => stream['codec_type'] === 'audio')
  53
  54     if (audioStream) {
  55       return {
  56         absolutePath: data.format.filename,
  57         audioStream,
  58         bitrate: parseInt(audioStream['bit_rate'] + '', 10)
  59       }
  60     }
  61   }
  62
  63   return { absolutePath: data.format.filename }
  64 }
  65
  66 function getMaxAudioBitrate (type: 'aac' | 'mp3' | string, bitrate: number) {
  67   const maxKBitrate = 384
  68   const kToBits = (kbits: number) => kbits * 1000
  69
  70   // If we did not manage to get the bitrate, use an average value
  71   if (!bitrate) return 256
  72
  73   if (type === 'aac') {
  74     switch (true) {
  75       case bitrate > kToBits(maxKBitrate):
  76         return maxKBitrate
  77
  78       default:
  79         return -1 // we interpret it as a signal to copy the audio stream as is
  80     }
  81   }
  82
  83   /*
  84     a 192kbit/sec mp3 doesn't hold as much information as a 192kbit/sec aac.
  85     That's why, when using aac, we can go to lower kbit/sec. The equivalences
  86     made here are not made to be accurate, especially with good mp3 encoders.
  87     */
  88   switch (true) {
  89     case bitrate <= kToBits(192):
  90       return 128
  91
  92     case bitrate <= kToBits(384):
  93       return 256
  94
  95     default:
  96       return maxKBitrate
  97   }
  98 }
  99
 100 // ---------------------------------------------------------------------------
 101 // Video
 102 // ---------------------------------------------------------------------------
 103
 104 async function getVideoStreamDimensionsInfo (path: string, existingProbe?: FfprobeData) {
 105   const videoStream = await getVideoStream(path, existingProbe)
 106   if (!videoStream) return undefined
 107
 108   return {
 109     width: videoStream.width,
 110     height: videoStream.height,
 111     ratio: Math.max(videoStream.height, videoStream.width) / Math.min(videoStream.height, videoStream.width),
 112     resolution: Math.min(videoStream.height, videoStream.width),
 113     isPortraitMode: videoStream.height > videoStream.width
 114   }
 115 }
 116
 117 async function getVideoStreamFPS (path: string, existingProbe?: FfprobeData) {
 118   const videoStream = await getVideoStream(path, existingProbe)
 119   if (!videoStream) return 0
 120
 121   for (const key of [ 'avg_frame_rate', 'r_frame_rate' ]) {
 122     const valuesText: string = videoStream[key]
 123     if (!valuesText) continue
 124
 125     const [ frames, seconds ] = valuesText.split('/')
 126     if (!frames || !seconds) continue
 127
 128     const result = parseInt(frames, 10) / parseInt(seconds, 10)
 129     if (result > 0) return Math.round(result)
 130   }
 131
 132   return 0
 133 }
 134
 135 async function buildFileMetadata (path: string, existingProbe?: FfprobeData) {
 136   const metadata = existingProbe || await ffprobePromise(path)
 137
 138   return new VideoFileMetadata(metadata)
 139 }
 140
 141 async function getVideoStreamBitrate (path: string, existingProbe?: FfprobeData): Promise<number> {
 142   const metadata = await buildFileMetadata(path, existingProbe)
 143
 144   let bitrate = metadata.format.bit_rate as number
 145   if (bitrate && !isNaN(bitrate)) return bitrate
 146
 147   const videoStream = await getVideoStream(path, existingProbe)
 148   if (!videoStream) return undefined
 149
 150   bitrate = videoStream?.bit_rate
 151   if (bitrate && !isNaN(bitrate)) return bitrate
 152
 153   return undefined
 154 }
 155
 156 async function getVideoStreamDuration (path: string, existingProbe?: FfprobeData) {
 157   const metadata = await buildFileMetadata(path, existingProbe)
 158
 159   return Math.round(metadata.format.duration)
 160 }
 161
 162 async function getVideoStream (path: string, existingProbe?: FfprobeData) {
 163   const metadata = await buildFileMetadata(path, existingProbe)
 164
 165   return metadata.streams.find(s => s.codec_type === 'video')
 166 }
 167
 168 // ---------------------------------------------------------------------------
 169
 170 export {
 171   getVideoStreamDimensionsInfo,
 172   buildFileMetadata,
 173   getMaxAudioBitrate,
 174   getVideoStream,
 175   getVideoStreamDuration,
 176   getAudioStream,
 177   getVideoStreamFPS,
 178   isAudioFile,
 179   ffprobePromise,
 180   getVideoStreamBitrate,
 181   hasAudioStream
 182 }